/* ════════════════════════════════════════════════════════════════
   Vega — 官网 · "Quant Terminal" 设计系统(对齐 desktop)
   暗色金融终端 · ticker amber 主色 · IBM Plex · 红涨绿跌
   ════════════════════════════════════════════════════════════════ */
:root{
  --base:#0a0c0f; --base2:#0e1116; --surface:#14181e; --surface2:#1a1f27;
  --line:#232a33; --line2:#313b47;
  --ink:#e8eaed; --dim:#98a0ab; --faint:#59616c;
  --amber:#f0a92b; --amber2:#ffc869; --ink-on-amber:#1a1205;
  --up:#ff5a52; --down:#16c784;
  --sans:"IBM Plex Sans","IBM Plex Sans SC",-apple-system,"PingFang SC",system-ui,sans-serif;
  --mono:"IBM Plex Mono",ui-monospace,"SF Mono",monospace;
  --maxw:1080px;
}
*{box-sizing:border-box;margin:0;padding:0}
html{scroll-behavior:smooth}
body{
  background:var(--base); color:var(--ink); font-family:var(--sans);
  line-height:1.6; -webkit-font-smoothing:antialiased; text-rendering:optimizeLegibility;
  overflow-x:hidden; position:relative; min-height:100vh;
}
a{color:inherit;text-decoration:none}
code{font-family:var(--mono);font-size:.86em;color:var(--amber2);
  background:color-mix(in oklab,var(--amber) 12%,transparent);padding:1px 6px;border-radius:5px}
em{font-style:normal;color:var(--amber2);font-weight:500}

/* ── atmospheric layers ─────────────────────────────────────── */
.bg-glow,.bg-grid,.bg-grain,.starfield{position:fixed;inset:0;pointer-events:none;z-index:0}
.bg-glow{
  background:
    radial-gradient(720px 460px at 82% -8%, rgba(240,169,43,.16), transparent 62%),
    radial-gradient(620px 420px at 6% 104%, rgba(240,169,43,.06), transparent 58%);
}
.bg-grid{
  background-image:linear-gradient(var(--line) 1px,transparent 1px),linear-gradient(90deg,var(--line) 1px,transparent 1px);
  background-size:56px 56px; opacity:.30;
  mask-image:radial-gradient(120% 90% at 50% 0%, #000 0%, transparent 72%);
  -webkit-mask-image:radial-gradient(120% 90% at 50% 0%, #000 0%, transparent 72%);
}
.bg-grain{opacity:.04;mix-blend-mode:overlay;
  background-image:url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='120' height='120'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='.9' numOctaves='2'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23n)'/%3E%3C/svg%3E");}
.starfield{
  background-image:
    radial-gradient(1.4px 1.4px at 12% 22%, rgba(255,200,105,.5), transparent),
    radial-gradient(1.2px 1.2px at 78% 14%, rgba(255,200,105,.4), transparent),
    radial-gradient(1px 1px at 42% 36%, rgba(232,234,237,.35), transparent),
    radial-gradient(1.3px 1.3px at 90% 40%, rgba(255,200,105,.35), transparent),
    radial-gradient(1px 1px at 28% 8%, rgba(232,234,237,.3), transparent);
  opacity:.7;
}

/* ── header ─────────────────────────────────────────────────── */
.site-header{
  position:sticky;top:0;z-index:20;display:flex;align-items:center;justify-content:space-between;
  padding:16px 28px;max-width:var(--maxw);margin:0 auto;
}
.site-header::before{content:"";position:absolute;inset:0;z-index:-1;
  background:color-mix(in oklab,var(--base) 72%,transparent);backdrop-filter:blur(12px);
  border-bottom:1px solid var(--line)}
.brand{display:flex;align-items:center;gap:10px}
.brand-mark{display:grid;place-items:center;width:36px;height:36px;border-radius:10px;
  background:linear-gradient(180deg,var(--amber2),var(--amber));
  box-shadow:0 6px 18px -8px rgba(240,169,43,.7)}
.brand-mark svg [fill="url(#glyphGrad)"],.brand-mark svg circle{fill:var(--ink-on-amber)}
.brand-mark svg polyline{stroke:var(--ink-on-amber)}
.brand-name{font-weight:600;font-size:17px;letter-spacing:.04em}
.site-nav{display:flex;align-items:center;gap:8px;font-size:14px}
.site-nav a{color:var(--dim);padding:8px 12px;border-radius:8px;transition:color .2s,background .2s}
.site-nav a:hover{color:var(--ink);background:var(--surface)}
.nav-cta{color:var(--amber2)!important;border:1px solid color-mix(in oklab,var(--amber) 40%,transparent)}
.nav-cta:hover{background:color-mix(in oklab,var(--amber) 14%,transparent)!important}

/* ── hero ───────────────────────────────────────────────────── */
.hero{position:relative;z-index:1;max-width:var(--maxw);margin:0 auto;
  padding:56px 28px 84px;display:flex;flex-direction:column;align-items:center;text-align:center}
.hero-mark{width:300px;height:250px;display:grid;place-items:center;margin-bottom:6px;
  filter:drop-shadow(0 10px 40px rgba(240,169,43,.22))}
.star-svg{transition:translate .25s cubic-bezier(.2,.7,.2,1)}
.hp-line{stroke-dasharray:240;stroke-dashoffset:240;animation:draw 1.2s cubic-bezier(.4,0,.2,1) .25s forwards}
.hp-dot{opacity:0;animation:pop .4s ease forwards}
.hp-dot:nth-of-type(1){animation-delay:.5s}.hp-dot:nth-of-type(2){animation-delay:.66s}.hp-dot:nth-of-type(3){animation-delay:.82s}
@keyframes draw{to{stroke-dashoffset:0}}
@keyframes pop{from{opacity:0;transform:scale(.4)}to{opacity:1;transform:none}}

.hero-eyebrow{font-family:var(--mono);font-size:12px;letter-spacing:.26em;text-transform:uppercase;color:var(--amber)}
.hero-wordmark{font-size:clamp(58px,11vw,104px);font-weight:700;letter-spacing:-.03em;line-height:.96;margin:8px 0 2px;
  background:linear-gradient(180deg,#fff 18%,var(--ink) 60%,#9aa2ad);-webkit-background-clip:text;background-clip:text;color:transparent}
.hero-tagline{font-size:clamp(19px,2.6vw,25px);font-weight:600;color:var(--ink);letter-spacing:-.01em}
.hero-sub{margin-top:16px;max-width:50ch;color:var(--dim);font-size:16px}
.hero-cta{display:flex;gap:12px;margin-top:30px;flex-wrap:wrap;justify-content:center}
.hero-note{margin-top:16px;font-family:var(--mono);font-size:11.5px;color:var(--faint);letter-spacing:.02em}

/* ── buttons ────────────────────────────────────────────────── */
.btn{display:inline-flex;align-items:center;gap:9px;font-family:var(--sans);font-size:14.5px;font-weight:600;
  padding:11px 20px;border-radius:11px;border:1px solid transparent;cursor:pointer;transition:transform .15s,box-shadow .2s,background .2s,border-color .2s}
.btn-primary{background:linear-gradient(180deg,var(--amber2),var(--amber));color:var(--ink-on-amber);
  box-shadow:0 10px 28px -10px rgba(240,169,43,.7)}
.btn-primary:hover{transform:translateY(-2px);box-shadow:0 16px 36px -12px rgba(240,169,43,.8)}
.btn-ghost{background:transparent;border-color:var(--line2);color:var(--ink)}
.btn-ghost:hover{border-color:var(--amber);color:var(--amber2);background:color-mix(in oklab,var(--amber) 8%,transparent)}
.btn-lg{padding:14px 26px;font-size:15.5px}
.btn-disabled{background:var(--surface);color:var(--faint);border-color:var(--line);cursor:not-allowed}
.apple-glyph{margin-top:-2px}

/* ── sections ───────────────────────────────────────────────── */
.section-title{font-size:clamp(28px,4.4vw,42px);font-weight:700;letter-spacing:-.02em;text-align:center;line-height:1.12}
.grad-text{background:linear-gradient(100deg,var(--amber2),var(--amber));-webkit-background-clip:text;background-clip:text;color:transparent}

.features{position:relative;z-index:1;max-width:var(--maxw);margin:0 auto;padding:40px 28px 24px}
.feature-grid{display:grid;grid-template-columns:repeat(2,1fr);gap:18px;margin-top:42px}
.feature{position:relative;border:1px solid var(--line);border-radius:18px;padding:26px 24px;
  background:linear-gradient(180deg,var(--base2),var(--base));overflow:hidden;transition:transform .25s,border-color .25s,box-shadow .25s}
.feature::before{content:"";position:absolute;inset:0;border-radius:inherit;padding:1px;opacity:0;transition:opacity .25s;
  background:linear-gradient(140deg,color-mix(in oklab,var(--amber) 55%,transparent),transparent 45%);
  -webkit-mask:linear-gradient(#000 0 0) content-box,linear-gradient(#000 0 0);-webkit-mask-composite:xor;mask-composite:exclude}
.feature:hover{transform:translateY(-4px);box-shadow:0 22px 50px -24px rgba(0,0,0,.8)}
.feature:hover::before{opacity:1}
.feature--lead{grid-row:span 2;display:flex;flex-direction:column}
.feature--lead h3{font-size:21px}
.feature--wide{grid-column:span 2}
.feature-idx{font-family:var(--mono);font-size:12px;color:var(--faint);letter-spacing:.1em}
.feature-icon{width:46px;height:46px;display:grid;place-items:center;margin:16px 0 14px;border-radius:12px;color:var(--amber);
  background:color-mix(in oklab,var(--amber) 12%,transparent);border:1px solid color-mix(in oklab,var(--amber) 26%,transparent)}
.feature h3{font-size:18px;font-weight:600;letter-spacing:-.01em;margin-bottom:8px}
.feature p{color:var(--dim);font-size:14.5px}
.feature--lead p{font-size:15px}

/* ── download ───────────────────────────────────────────────── */
.download{position:relative;z-index:1;max-width:var(--maxw);margin:48px auto 0;padding:0 28px}
.download-inner{position:relative;overflow:hidden;border:1px solid var(--line2);border-radius:24px;
  padding:60px 28px;text-align:center;background:
    radial-gradient(120% 140% at 50% -20%, rgba(240,169,43,.14), transparent 60%),
    linear-gradient(180deg,var(--base2),var(--base))}
.download-glow{position:absolute;inset:0;pointer-events:none;
  background:radial-gradient(420px 200px at 50% 0%, rgba(255,200,105,.18), transparent 70%)}
.download-lede{margin:14px auto 0;color:var(--dim);max-width:46ch;font-size:15.5px}
.download-actions{display:flex;gap:12px;justify-content:center;flex-wrap:wrap;margin-top:30px;position:relative}
.download-note{margin-top:18px;font-family:var(--mono);font-size:11.5px;color:var(--faint)}

/* ── footer ─────────────────────────────────────────────────── */
.site-footer{position:relative;z-index:1;max-width:var(--maxw);margin:64px auto 0;
  padding:40px 28px 56px;display:flex;align-items:center;justify-content:space-between;gap:16px;flex-wrap:wrap;
  border-top:1px solid var(--line);font-size:13px;color:var(--faint)}
.footer-brand{display:flex;align-items:center;gap:10px}
.footer-brand span{color:var(--dim)}
.footer-by a{color:var(--amber2)}
.footer-by a:hover{text-decoration:underline}

/* ── reveal animations ──────────────────────────────────────── */
.reveal{opacity:0;transform:translateY(16px);animation:reveal .7s cubic-bezier(.2,.7,.2,1) forwards;animation-delay:var(--d,0s)}
@keyframes reveal{to{opacity:1;transform:none}}
.in-view-target{opacity:0;transform:translateY(22px);transition:opacity .7s cubic-bezier(.2,.7,.2,1),transform .7s cubic-bezier(.2,.7,.2,1)}
.in-view-target.is-visible{opacity:1;transform:none}

/* ── responsive ─────────────────────────────────────────────── */
@media (max-width:720px){
  .feature-grid{grid-template-columns:1fr}
  .feature--lead{grid-row:auto}.feature--wide{grid-column:auto}
  .hero{padding-top:32px}
  .hero-mark{width:230px;height:192px}
}
@media (prefers-reduced-motion:reduce){
  *{animation-duration:.001ms!important;animation-delay:0s!important;transition-duration:.001ms!important}
  .reveal,.hp-dot{opacity:1;transform:none}.hp-line{stroke-dashoffset:0}
  html{scroll-behavior:auto}
}